Automatic knife blade grinding machine



March 21, 1939. Q LUDWIG 2,151,480

AUTOMATIC KNIFE BLADE GRINDING MACHINE Filed May 14, '19s? 6Sheets-Sheet 1 II I muml

M INVENTOR BY M 4 ATTORNEY.

March 21, 1939. c. LUDWlG 2,151,480

AUTOMATIC KNIFE BLADE GRINDING MACHINE Filed May 14, 1937 G-Sheets-Sheet2 mvrsgvrok.

March 21, 1939. c. LUDWIG AUTOMATIC KNIFE BLADE GRINDING MACHINE FiledMay 14, 1957 6 Sheets-Sheet 3 IN VENT OR.

I ATTORNY.

March 21, 1939. c, u|: w|c;

I AUTOMATIC KNIFE BLADE GRINDING MACHINE Filed May 14, 1957 6Sheets-Sheet 4 INVENTOR.

MM ATTORNEY.

March 21, 1939.

C LUDWIG AUTOMATIC KNIFE BLADE GRINDING MACHINE Filed May 14, 1937 6Sheets-Sheet 5 /a5/ .llll -i //8 1712.151 4k /2, 5] 1-- IZZ Mal-ch21,1939. c wf 2,151,480

AUTOMATI'G; KNIFE BLADE GRINDING MACHINE Filed May 14 193-7 6 Sheets-Sheet 6 IDVenfor;

ATI'OR X Patented Mar. 21, 1939 UNlTED STATEfi AUTOMATIC KNIFE BLADEGRINDING MACHINE Clarence Ludwig, Bluffton, Ind.

Application May 14, 1937, Serial No. 142,553

5 Claims.

This invention relates to improvements in automatically operatingmachines for grinding and regrinding knife blades that have a serratededge, or of the type used generally in bread slic- 5 ing machines.

An object of the invention is to provide a machine .that is automatic inoperation and which has adjustable means associated with its variousparts so that in grinding a blade a serrated sharp i edge is formed withuniform and accurately spaced crests.

Another object of the invention is to provide in an automatic knifeblade grinding machine movable supporting means arranged so that a 15knife having a serrated edge is moved in contact with a grindstone andprogressed regularly so that the grinding action of the grindstone uponthe blade follows uniformly along the serrated edge of the bladethroughout the length thereof.

20 This object includes also adjusting means so arranged as to regulatethe stroke of the bladefeeding apparatus to conform accurately with thespacing of the serrations of the blade, this being highly desirableespecially in regrinding or re- 25 sharpening serrated knife blades.

A further object is to provide a mechanism for advancing a knife bladewhile contacting a grindstone in a sequence of uniform progressivemovements and for oscillating said blade in an arcuate 30 coursesynchronically with said progressive movements to thereby dress theblade along its serrated edge to an even bevel.

Other objects and advantages of the invention are shown in the followingdescription.

35 An illustrative embodiment of the invention is shown in theaccompanying drawings, in which: N

Fig. 1 is a top plan view of the frame and certain of the movablemembers of the machine,

40 parts being in section; I

Fig. 2 is a fragmentary front elevation of the machine;

Fig. 3 is a fragmentary side elevation of the machine, parts thereofbeing shown in section;

45 Fig. 4 is a fragmentary plan view of a knife blade holder andoscillating means therefor, parts being broken away;

Fig. 5 is a detail View of the knife blade holder showing the grippingmeans therefor, portions 50 being shown in section;

Fig. 6 is a detail view showing a side elevation of the feedingmechanism for the knife blade holder, parts being in section;

Fig. 'l is a detail front elevation of the feeding 55 mechanism for theknife blade holder;

Fig. 8 is a detail View, partly in section, showing the mounting for thegrindstone;

Fig. 9 is an elevation, partially broken away and in section, showing ahydraulic oscillator for actuating the knife blade holder;

Fig. 10 is a plan view of a part of the oscillator;

Fig. 11 is a detail view showing a side elevation of one of themagnetically-operated valves used in the apparatus, portions beingbroken away; 10

Fig. 12 is a detail plan view of an air pressureoperated switch forcontrolling electric circuits used in the appliance;

Fig. 13 is a top plan view of one of the electromagnets used in theappliance; 15

Fig. 14 is a side view of the electro-magnet; Fig..15 is a diagram ofthe electrical, pneumatic and hydraulic arrangement of the connectionswith the parts associated therewith; and

Fig. 16 is a perspective view of the machine. 20

In the illustrative embodiment of the invention there is shown a machineframe constituted of side members i, end members 2 and legs 3 connectedto the side and end members for elevated support of said members.

In the frame is mounted a platform which has adjustable movementrelative thereto. The platform is constituted of parallel bars lsuitably spaced apart, the ends of which extend through the end members2 of the frame and are longitudinally movable therein. The extendingforward ends of the bars 4 are connected by a crossbar 5 upon which ismounted an oscillator 6, hereinafter described, and are also connectedby a transversely disposed bracket 1 preferably 10- cated at a pointspaced back from the forward frame member 2. Upon the top of the bracket1 is a forwardly extending brace 8 that is connected with the oscillator6 and affords supplemental support therefor.

The bars 4 have secured thereto a transversely disposed plate 9 uponwhich is mounted a series of electro-magnetically controlled air-valvesH], H, l2 and i3, hereinafter described.

Upon the rear portions of the bars 4 within the frame are securedcollars M, and compression springs i5 are disposed concentrically uponsaid bars between the collars i l and the rear end frame member 2. Across-beam i6 is disposed on the bars a, said bars extending through thecorresponding ends of the beam, and said beam bears against said collarsM in opposition to the resistance of the springs l5. An adjusting shaftll extends through the rear frame member 2 and has threaded relationwith the beam IS. The

rear extending end of the shaft II has secured thereon a gear l8 thathas engagement with a pinion I!) on a shaft 20 which is mounted in aframe member 20'. An operating rod 2| is connected with the shaft 20 bymeans of a universal coupling 22. The forward end of the operating rod2| extends loosely through one of the foremost legs 3 and is providedwith a hand-wheel 23. Upon turning of the hand-wheel the shaft I1 isaccordingly turned whereupon the platform is moved backwardly inopposition to the springs IE or is permitted to move forwardly byreaction of said springs according to the direction of the turningmovement of the shaft H. In this manner the platform is adjustedlongitudinally with respect to the frame. A safety guard 24 ispositioned on the back of the frame and encompasses the gear l8 andpinion l9.

Knife blade holder A swing-head 25 is secured upon the stem 26 of theoscillator 6, and has on its outer end a face-plate 21. Vertical guiderods 28 are positioned respectively adjacent the ends of the faceplatein lugs 29 secured on said plate and have vertical sliding movement insaid blocks, and upon each guide rod is secured a block 30 that hasvertical movement therewith. In the blocks 30 is mounted a horizontalshaft 3| that has axial sliding movement therein, and an adjustingsleeve-nut 32 threaded on said shaft limits the stroke of the shaft inone direction by coming into contact with the adjacent block 30. Thus,the operator, by turning the nut 32 is enabled to initially set theshaft at a definite selected position.

Upon each end of the horizontal shaft 3| is secured a vertical arm 33and 34 respectively and upon the lower ends of said arms is secured atransversely disposed iron bar 35. Also, upon the lower ends of theguide rods 28 are secured blocks 36 uponthe outer faces of which the bar35 has longitudinal sliding movement. The blocks 36 are connected by atransverse bar 31 the ends of which are secured respectively to thebottoms of the blocks 36. I

The blocks 30, shaft 3|, arms 33 and 34 and the bar 35 together with theblocks 36, transverse bar 31, and the guide-rods 28 constitute atraverse unit that has supported relation with the swing-head and haslateral traverse and vertical movement relative thereto.

A bracket 38 'is secured to the face-plate 21 at the lower end thereofand is provided with an adjusting screw 39 upon which rests the traverseunit. By turning the screw 39 the traverseunit is adjustably raised orlowered relative to the face-plate 21. i

A horizontal shaft 40 is mounted with its ends extending respectively inthe blocks 30, and on said shaft between said blocks is secured a hanger4| having attached to its lower end an electromagnet 42, the poles ofwhich are positioned immediately adjacent the front face of thetransverse bar 35 so that when the magnet is energized the bar isengaged thereby.

Upon one of the blocks 30 is mounted an air cylinder 43 one end of whichis closed to provide a piston chamber, and an air supply pipe 44 hascommunication with said chamber through its closed end. One end of theshaft 4|], to which the hanger 4| is secured, extends into the pistonchamber and has secured thereon within the chamber a piston 45.

Upon entrance of air under pressure into the chamber movement isimparted to the piston and the shaft 40 attached thereto, whereupon, thehanger 4| is moved accordingly. A compression spring 46 isconcentrically disposed upon the shaft 40 and acts against the piston 45so that upon release of air from the piston chamber the hanger isreturned to its initial position by action of the spring. An adjustablestop 4'! on the hanger 4| is provided to limit the stroke thereofuponcoming against an electric contactor 41 on the adjacent block 33. Byadjustably turning the stop 41 the length of the stroke of the hanger isvaried accordingly. When the electro-mag-net 42 is energized and thetransverse bar 35 is engaged thereby and air is simultaneously admittedto the piston chamber, the traverse unit is progressed a definitedistance.

Upon the upper part of the face-plate 21 are secured lugs 48 spacedapart, in which is disposed a shaft 49 upon which is secured a tiltingblock 50 having secured upon its outer end an air cylinder one end ofwhich is closed to provide a piston chamber, and an air supply pipe 52has communication with said chamber through its closed end. The block 50has a pendent lug 53 through which loosely extends a screw 54 that ismounted in the face-plate 21, there being provided a compression spring55 between said lug and face-plate which yieldingly supports the aircylinder 5| normally in its uppermost position.

In the tilting block 50 are disposed spring-re strained plunger pins 56that are moved longitudinally by action of a piston 51 in the aircylinder 5| upon entrance of air under pressure into the piston chamber.Upon the outer end of each plunger pin is secured a butt-head 58disposed opposite the inner face of a guard-plate 59 supported inconnection with the tilting block so that when a knife blade 60 ispositioned between the butt-heads and the guard-plate, and air underpressure is introduced into the piston chamber, the plunger pins arethrust forwardly and the knife blade is clamped against the guardplate.Thus, when the knife-blade is clamped in place and the traverse unit issimultaneously progressed, the knife blade is moved accordingly. Theupper extending end of one of the arms 33 has adjustably secured thereina horizontally disposed blade-attaching rod 6| having at one end a pin62 adapted to have connection with the knife blade 60, there being holes64 adjacent the ends of the knife blade for the reception of the pin.Also, on the rod is disposed a spring-pressed sleeve 65 that bearsagainst the adjacent end of the knife blade when connected with the rod,so that the blade is secured in a definite position relative to the rod.

Oscillator The swing-head 25 is actuated by the oscillator 6 whichconsists of a hollow base 66 that is secured on the cross-bar 5, anoscillating member 61, a head 68 for confining said member in the baseand a bonnet 69 threaded on the base to hold the head in place. Theaxial stem 26 on the oscillating member extends through the bonnet, andpackings II and 12 are provided to prevent leakage from the bonnet. Thebase and bonnet have threaded relation so that upon turning the bonnetupon the base the packing H is compressed, and a ring 13 threaded on thebase is provided for compressing the packing 12.

The base 66 has therein oppositely disposed vanes '|4-'|4 so that twoseparate semi-circular Chambers 15-15 are provided, and the oscillatingmember has oppositely disposed vanes I6- 16 that extend] respectivelyinto said chambers and have movement therein between the correspondingvanes. Each vane has therein a port 71 11 for ingress and egress offluid with respect to the chamber I5, and the hub of the oscillatingmember has made therein ducts I8'I8 through which liquid, admittedthrough one of said ports, flows into or from said chambers according tothe movement of fluid through said ports. For instance, as fluid entersthe base through port ll the flow continues through the duct I8 andconsequently the vanes 16 and I6 are moved clockwise because of thepressure of liquid in the Chambers. coincidentally, outflow of fluidthrough duct I8 and 1'! takes place. When, however, fluid under pressureenters through port TI and passes through duct I8, the oscillatingmember is thereupon moved counter-clockwise, and concurrently, outflowof fluid from said chambers through duct I8 and port 11 takes place.Upon operation of the oscillating member the swing-head 25 is actuated.

The oscillator 6, preferably, is motivated by liquid supplied undercontrol of electro-magnet operated air valves II] and I2. For thispurpose there are provided two reservoirs I9 and that have pipeconnections I9 and 80 respectively with the ports 1'! and H in theoscillator. Said pipe connections each have a hand-operated valve 8| bywhich flow of liquid through the corresponding pipe connections isregulated. The reservoirs are filled with liquid, preferably oil, andhave means in connection therewith, hereinafter described, by whichmomentary pressure is applied alternately thereto. By adjustably turningthe valves 8! the speed of the oscillator is regulated.

Controlling unit The apparatus for automaticallycontrolling operation ofthe swing-head and traverse unit is constituted of the series ofelectro-magnetically operated air valves 10, II, It and I3 and theswitch-controlled circuits hereinafter described. Each of said switches,preferably, (Fig. 11) has an air receiving chamber 82 that is closed atits lower end by a needle valve 83, the upper end of which has thereonan iron disc 174 that is attracted by an electro-magnet 85 when themagnet is energized. The magnet is located on the closed top of thereceiving chamber 82. Air under pressure is supplied from a suitablesource to the air chamber through an inlet pipe 86 and the lower end ofthe chamber is threaded in the upper end of a hollow base 81 that isprovided with an outlet pipe 88. The lower end of the base has anexhaust pipe 89 provided with a needle valve 99 that is closed by actionof another electro-magnet 9|. The magnet 9| is hinged to the bottom ofthe iron plate 9 and has a laterally extending arm 92 connected with theneedle valve at so that when the magnet BI is energized it is swung upagainst the iron plate by magnetic attraction causing the needle valveto close. A bracket 93 secured to the plate is arranged to limit openingmovement of said needle valve and swinging movement of the magnet. Themagnets 85 and iii are connected in parallel with conductors 94 so thatsaid magnets are simultaneously energized. Thus, when the air valve 83is raised to open position, the exhaust valve as is simultaneouslyclosed, and when said magnets are de-energized' the valve 83 is closedand the exhaust valve 90 is opened.

, The outlet pipe 88, connected with the hollow base 8'! of the valveI2, has communication with the upper end of the reservoir 80 through aconnection S5, and the hollow base of the valve H has similarcommunication with the reservoir 79 through a connection at. Thus, uponalternate operation of the valves I2 and H, air pressure is accordinglyapplied to said reservoirs which causes the liquid in said reservoirs toflow to and from the oscillator, thus actuating same.

The outlet pipes 88 of the air valves in and I3 have communicationsrespectively through tubes It and i3 with the air cylinders 43 and 5| sothat upon operation of said air valves the pistons in said air cylindersare actuated.

Pressure switches The hollow bases Bl of the air valves l I and I! haveconnected therewith corresponding air pressure operated electricswitches 53? and 98 respectively that are operated pneumatically whenair pressure is raised in the corresponding valve bases Bl.

Each pressure switch (Figs. 11 and 12) consists of a supported arcuatetube 99 that is connected at its supported end with the correspondingvalve base 81 by means of a pipe I60, and the free end of said tube hasswitch members IM and I02 that are operatively associated withadjacently positioned contactors I03 and I04 respectively.

Normally, the switch member I92 and contactor Iil i are closed and theswitch member Hill and contactor Hi3 are open. When air pressure israised in the corresponding valve base, the arcuate tube becomes therebydistended so that switch member I02 is moved to open position and switchmember IUI is closed.

With respect to the pneumatically-operated switch 98 the switch membersare indicated by M5 and I06 respectively, the same being comparable withthe switch members IGI and I02 respecting the pneumatic switch 91.

There are provided on the traverse unit automatically-operated switchesiii? and I08. The switch it? normally is open and is closed whencontacted by the stop ll upon completion of each forward stroke of thetraverse unit. The switch 508 normally is closed by movement of thetraverse unit to its initial starting position when an arm Itt on thetraverse bar 35 contacts with and moves a sliding rod I It that ismounted in the blocks 2s, whereupon the switch Itii is closed. Uponcompletion of the left-hand movement of the traverse bar at an arm ii Icontacts with and moves the red I iii in the opposite direction therebyopening the switch EM which is constituted of a spring-plate H2 attachedto the hanger M and a contactor IE3 on the rod Hi].

There are provided automatically-operated control switches Hit and M5associated with the platform and the face-plate on the swing-head 25.Upon completion of the left-hand movement of the swing-head, the switchH4 is closed, and upon completion of the right-hand movement of theswing-head the switch IE5 is opened.

These actions are occasioned by engaging brackets I06 and Iii securedrespectively on the opposite ends of the face-plate 21.

There is also provided a manually-operated starting switch H3, closingof which causes the electro-magnetically controlled switch I I3 to openand consequent initial action of the oscillator 6.

The magnet coils on the air valves it, M, ii and it each have connectionwith a bus-wire I it that is connected with a rectifier I26 throughwhich electric current is supplied to the apparatus; The rectifier alsohas a ground connection I2I.

Electrical connections are established between the various switches, theelectro-magnet 42 and the electro-magrlets on the air valves I0, II, I2and I3 by conductors suitably arranged. Viz: The traverse unit movingmagnet 42 and the electro-magnet for the air valve I are connected inparallel by conductors I22 and I 23, and the conductor I22 is connectedwith the switch I06 by a conductor I24 so that when the switch I06 isclosed the magnet 42 and valve'l0 function and consequently the traverseunit is progressed through the medium of the air actuated piston 45.

The switch II normally is open and has connection with the air valve I3through conductors I25 and I26, and the manually-operated switch H8 alsohas connection with the air valve I3 through conductors I21 and I26,said switch being grounded by a connection I28.

The switch I08, by conductors I29 and I24 and switch I06, when closed,completes the electrical circuit through the magnet coils on the airvalve I0 and on the magnet 42 that engages the traverse unit.

The magnet coil on the valve I2 has connection with the switch II4through conductor I30, and the air pressure controlled switch IOI alsohas connection withsaid air valve magnet coil I2 through a conductorI3I. The switches IOI, I02, and I05 are connected by conductors I32 andI33, and the switch member I02 has connection with the coil of theelectro-magnetically-operated air valve II through a conductor I34.

Grinding element Upon the main frame are positioned forwardly extendingbeams I35, one of which supports a ball bearing I36 and the other beingprovided with a stub-shaft I3'I axially alined with said bearing, andupon said stub-shaft preferably is mounted a roller bearing I38. Agrinding element, consisting of a grindstone I39, is mounted upon afixture constituted of a pulley I40 that is supported on said rollerbearing, and a stud I4I that is supported in said ball bearing.

Rotary movement is imparted to the grindstone I39 by means of a motorI42 through the medium of a belt I 43. The cutting edge of thegrindstone is initially positioned immediately back of the'guard-plate59 and has grinding action on the blade 60 when said blade is pressedinto place against said guard-plate and the swing-head is in motion.

The inlet pipes 86 of the air valves I0, II, I2 and I3 have connectionwith a supply pipe I 44 through which air is supplied thereto underpressure from a suitable source. For convenience, there is provided anair compressor I45 in juxtaposition with the motor I42 arranged to beactuated by a belt I46 and pulleys I41 and I 48 operatively connectedrespectively with the motor and compressor.

In connection with the traverse unit preferably attached to the blocks30, are provided blade-supporting brackets I49 by means of which theblade 60 is sustained in operative position when connected with theblade-attaching rod 6|.

Operation In operation, the traverse unit is first moved right-handedlyuntil stopped by contact of the sleeve 32 with the adjacent block 30.The knife blade 60 then is connected with the rod BI and secured thereonby the spring-pressed sleeve 65. The back of the blade rests upon and issupported by the brackets I49 while disposed between the butt-heads 53and the guard-plate 56. The operator then by closing the switch II8causes action of the electro-magnetically-operated valve I3, whereuponair enters the air cylinder 5I, causing movement of the plunger pins andclamping action of the butt-heads against the blade thereby holding theblade against the guard-plate.

Upon operation of the valve 13 the air pressure switch 98 is actuated,whereupon the switch I05 is closed which affords a ground connectionthrough closed switch I02 with the electro-magnetically-operated airvalve I I, thus admitting air pressure into the reservoir 19 andconsequent movement of the oscillator 6 in one direction. Thus, theswing-head is actuated permitting the switch H5 to close, and uponcompletion of the stroke of the swing-head the switch I I4 is closed,whereupon the electro-magnetically-operated air valve I2 is actuated,thus admitting air under pressure into the reservoir 80 and consequentmovement of the oscillator and swing-head in the opposite direction, andconcurrent opening of the switch I I4. During operation of the air valveI2 the pressure switch 91 is actuated causing switch I02 to open andthus release the air valve I I which permits return of liquid from theoscillator 6 back into the reservoir I9. Also, the air valve I2 ismomentarily maintained in operation through action of the pressure valve97 which causes closing of the switch IiiI, whereupon the circuitthrough valve I2 is completed by grounding through closed switch I05.When the swinghead engages the switch I I5 said switch is opened causingrelease of the valve I3, whereupon by action of the pressure valve 98the switch I05 is opened and consequently the air valve I2 is releasedwhich permits the switch Iil2 again to close. Thus, the air valves I6and I2 are operated alternately causing continuous action of theoscillator and swing-head attached thereto.

When the traverse frame is initially moved to starting position, asabove described, the arm I09 on the traverse bar 35 engages and movesthe sliding rod I II) which causes the switch I08 to close by engagementof the contactor H3 with the spring-plate I I 2, and thus is establishedcurrent through closed switch I06 thereby energizing the electro-magnet42 and the air valve IE! simultaneously. The electro-magnet 42 engagesthe traverse bar 35 and the air valve l0 admits air under pressure tothe cylinder 43 and consequent movement of the piston 45. In this mannerthe traverse unit is moved to an extent limited by closing of the switchI 6! which causes operation of the air valve I3 and consequent admissionof air into the cylinder 5!, thus causing the blade 60 to be pressedagainst the guardplate. By operation of the air valve I0 and magnet 42,the traverse unit is progressed left-handedly in a sequence of movementsequal in extent until the traverse unit reaches the point where the armIII on the traverse bar engages the sliding rod II 0 and causes openingof the switch I 08, which action terminates the operation of themachine.

During the left-hand travel of the traverse unit the upper edge of theknife blade 60 is subjected to the action of the grindstone at spacedintervals on the side thereof adjacent the grindstone. After the machineis stopped, by opening of the switch I08, the blade is disconnected bythe operator and turned end for end and again connected to theblade-attaching rod 6|. The traverse unit is then again manuallyreplaced in its starting position which causes closing of the switchI08.

The operation of the machine is re-started by closing themanually-operated switch H8. By operating the machine in the manner setforth the knife blade is ground upon one edge that present a series ofequally spaced uniform crests: between which the blade is beveled to asharp edge.

The illustrative embodiment of the invention is exemplary and is subjectto variations in struc ture and arrangements of parts, which would stillaccomplish the same end, by exercise of engineering skill, withoutdeparting from the spirit of the invention. Therefore, the claims areintended to encompass such variations in structure and rearrangement ofparts.

What I claim is:

1. A knife blade grinder, consisting of a supporting frame havingthereon a motor-driven grindstone and an adjustable platform includingmeans for adjusting same, an oscillator mounted on the platform havingsecured thereto a swinghead, a traverse unit operatively associated withsaid swing-head provided with a knife blade holding means and aguard-plate disposed between said grindstone and blade, an air pressureactuated member adapted periodically to press said blade against saidguard-plate, an electro-magnet engageablewith said traverse unit,another air pressure actuated member for moving said traverse unitsimultaneously with the action of said electro-magnet,electro-magnetically operated air valves for supplying air underpressure to said air pressure actuated members, liquidcontainingreservoirs having connections with said oscillator connectedrespectively with the opposite ports thereof, otherelectro-magnetically-operated air valves having connections respectivelywith said reservoirs arranged to supply air under pressure to saidreservoirs alternately, air pressure operated switches connectedrespectively with one of the first-mentioned air valves and with one ofsaid other air valves, switches operatively associated with theswing-head having controlling connections with the last-mentioned airvalves, electrical connections actuated by said air pressure switchesbetween said electro-magnetically operated air valves controlled by saidair pressure switches, automatically-operated switches associated withthe traverse unit through which movement thereof is controlled, and amanually operated switch connected with one of the electro-magneticallycontrolled air valves for starting ope-ration of the machine.

2. In a knife blade grinding machine, a supported grindstone havingactuating means therefor, an oscillator juxtaposed with respect to saidgrindstone and having actuating means therefor,

a swing-head operatively connected with said oscillator, a traverse unitcarried by said swinghead provided with means for imparting theretosequential movements in one direction synchronically with the action ofsaid swing-head, means on said traverse unit for connecting thereto aknife blade to be ground, supports on said swinghead to sustain saidknife blade, and a springpressed tilting block on said swing-headprovided with a guard-plate disposed adjacent said grindstone and havinga periodically operated means for clamping said blades against saidguardplate into position to be ground synchronically with respect to theaction of said swinghead.

3. In a knife blade grinding machine, a supported grindstone havingactuating means therefor, an oscillator juxtaposed with respect to saidgrindstone and having actuating means therefor, a swing-head operativelyconnected with said oscillator, a traverse unit carried by saidswinghead having a knife blade attaching member, and provided with meansfor imparting thereto sequential movements in one directionsynchronically with the action of said swing-head, and a spring-pressedtilting block on said swing-head provided with a guard-plate disposedadjacent said grindstone and having a periodically operated means forclamping said blades against said guard-plate into position to be groundsynchronically with respect to the action of said swing-head.

4. In knife blade grinding machine, a stationary frame, a platformmember adjustably movable on said frame,apower-driven grindstone havingsupported connection with said frame, an oscillator supported on saidplatform, a swing-head supported on and actuated by said oscillator,said swing-head having mounted therein a traverse member relativelymovable with respect thereto provided with a knife-securing means, aknifeclamping means supported by said swing-head adapted when actuatedto grip said blade and hold it in grinding position, automatic means forprogressing said traverse member through successive stages of movementrelative to said swing-head, and means for actuating the oscillator,knife-clamping means and for controlling said automatic means.

5. A knife blade grinding machine having a supported power-drivengrindstone, a swing-head disposed to have arcuate oscillatory movement,a knife blade holding traverse member movably mounted in saidswing-head, a knife clamping means supported by said swing-head adaptedwhen actuated to clamp said blade and hold it in grinding position,means for progressing said traverse member through successive stages ofmovement relative to said swing-head, and means for actuating saidswing-head, knife clamping means and said traverse member in timedsequence.

CLARENCE LUDWIG.

